操作数类型冲突：日期与 smallint 不兼容

Question

I want to create this table in SQL Server But it show date is incompatible with smallint error.

CREATE TABLE Trainees
(
    traineeID NCHAR(6) NOT NULL 
    CHECK  (traineeID LIKE '[0-9][0-9][0-9][0-9][0-9][0-9]') PRIMARY KEY,
    traineeName NVARCHAR (60) NOT NULL,
    traineeDOB DATE NOT NULL 
    CHECK (YEAR (traineeDOB) >=1991 AND NOT (traineeDOB) <=2002), 
    graduationYear DATE NOT NULL 
    CHECK (YEAR (graduationYear) >=2010 AND NOT (graduationYear) >=2021),
    Email NVARCHAR (50) NOT NULL UNIQUE,
    Phone NCHAR(11) NOT NULL 
    CHECK (traineeID LIKE '[0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9]'),
    enrolledCourse INT REFERENCES Course (courseId) NOT NULL

)
GO

Answer 1

In your CHECK restrictions you are comparing a DATE with a smallint (traineeDOB) <=2002 and (graduationYear) >=2021 . You should compare with a YEAR (smallint) with smallint, not DATE:

CREATE TABLE Trainees
(
    traineeID NCHAR(6) NOT NULL 
    CHECK  (traineeID LIKE '[0-9][0-9][0-9][0-9][0-9][0-9]') PRIMARY KEY,
    traineeName NVARCHAR (60) NOT NULL,
    traineeDOB DATE NOT NULL 
    CHECK (YEAR(traineeDOB) >=1991 AND NOT YEAR(traineeDOB) <=2002), 
    graduationYear DATE NOT NULL 
    CHECK (YEAR(graduationYear) >=2010 AND NOT YEAR(graduationYear) >=2021),
    Email NVARCHAR (50) NOT NULL UNIQUE,
    Phone NCHAR(11) NOT NULL 
    CHECK (traineeID LIKE '[0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9]'),
    enrolledCourse INT REFERENCES Course (courseId) NOT NULL

)
GO